MainActivity.java
public class MainActivity extends Activity {
/*声明控件对象*/
private EditText editText1,editText2;
private Button button1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/*取得控件对象*/
editText1=(EditText) findViewById(R.id.editText1);
editText2=(EditText) findViewById(R.id.editText2);
button1=(Button) findViewById(R.id.button1);
/*为按钮绑定监听器*/
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
int a = Integer.parseInt(editText1.getText().toString());
int b = Integer.parseInt(editText2.getText().toString());
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("editText1", a);
intent.putExtra("editText2",b);
/* 取得输入框中的内容
String str1=editText1.getText().toString();
String str2=editText2.getText().toString();
//创建Intent对象,参数分别为上下文,要跳转的Activity类
Intent intent=new Intent(MainActivity.this,SecondActivity.class);
//将要传递的值附加到Intent对象
intent.putExtra("editText1",str1);
intent.putExtra("editText2", str2);*/
//启动该Intent对象,实现跳转
startActivity(intent);
}
});
}
}
SecondActivity.java
public class SecondActivity extends Activity {
// 声明TextView对象
private TextView tv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.sencond);
// 取得TextView对象
tv = (TextView) findViewById(R.id.tv);
// 取得启动该Activity的Intent对象
Intent intent = getIntent();
int a = intent.getIntExtra("editText1", 0);
int b = intent.getIntExtra("editText2", 0);
int result=a+b;
tv.setText(a+" + "+b+" = "+result);
/* // 取出Intent中附加的数据
String str1 = intent.getStringExtra("testEdit1");
String str2 = intent.getStringExtra("testEdit2");
// 计算得到结果
int result = Integer.parseInt(str1) + Integer.parseInt(str2);
// 设置TextView显示的文本
tv.setText("计算结果为:" + String.valueOf(result));*/
}
}
在学习putExrta值传递时候,想把第一个Activity输入的数字传递到第二个,之前用注释语句的方法实现(把字符串传递过去后转换int),但是传过去的是空值,后面把输入的值先强制转换为int,再传递过去就正常,这是什么原因,请大神指导!